In recent years, a greenhouse effect caused by CO2 has been pointed out as one of factors of global warming, and a countermeasure thereof is urgently needed in worldwide in order to keep a global environment. As the generation source, CO2 is generated in the action field of every person who consumes fossil fuel, and there is a tendency that the suppression of the emission is further strongly demanded. Thus, an air pollution control system and an air pollution control method for a power generation facility such as thermal power plant using a large amount of fossil fuel have been actively examined. Here, in the air pollution control system and the air pollution control method, a flue gas generated from an industrial facility such as a boiler or a gas turbine is brought into contact with an amine CO2 absorbent, CO2 in the flue gas is removed and recovered, and the recovered CO2 is stored without being discharged to the atmosphere.
As a process of removing and recovering CO2 from the flue gas by using the above-described CO2 absorbent, there is disclosed a CO2 recovery device including a process of bringing a flue gas into contact with a CO2 absorbent in a CO2 absorber (hereinafter, simply referred to as an “absorber”) and a process of heating the CO2 absorbent (hereinafter, simply referred to as an “absorption solution”) absorbed CO2 in the absorption solution regenerator (hereinafter, simply referred to as a “regenerator”) so as to recover CO2 and regenerating the CO2 absorbent and to use the CO2 absorbent again in a circulation state in the CO2 absorber (for example, see Patent Literature 1).
In the CO2 absorber, for example, a counter-current contact occurs by using an amine CO2 absorbent such as alkanolamine, CO2 in the flue gas is absorbed to the CO2 absorbent by a chemical reaction (an exothermic reaction), and the flue gas from which CO2 has been removed is discharged to the outside of the system. The CO2 absorbent which absorbed CO2 is also referred to as a rich solution. The rich solution is boosted by a pump, is heated by a heat exchanger through a high-temperature CO2 absorbent (a lean solution) regenerated by recovering CO2 in a regenerator, and is supplied to the regenerator.